A computed tomography (CT) is a common endoscopy detection technology in the modern medicine. The CT technology obtains an image of a detected region of a human body by mainly rotating X-ray beams and a detector around the human body, and continuously carrying out section scanning, receiving attenuated X-ray information penetrating the human body by the detector and inputting said information into a computer, reconstructing an image through the computer based on the received attenuated X-ray information during each scanning.
The image reconstruction in the CT technology is an important factor that would affect the detection result. How to clearly and accurately reproduce an image of the detected region is a problem that has always been studied by the person skilled in the art.
From an imaging principle of a CT system, there are multiple factors that would affect a quality of a CT image. For example, in the existing CT system, due to reasons on the structure and manufacturing process of the detector itself, there would inevitably be some performance difference between detector cells on the detector, i.e., there would be some detector cells with performance difference. Projections sensed by those detector cells with performance difference cannot accurately reflect the image of the detected region, thus cannot be applied to the CT image reconstruction directly.
An existing processing method is: in the case that the detector cells with performance difference are determined to be present, usually by an interpolation method, a projection on the detector cell with performance difference is estimated from projections sensed on two detector cells adjacent to the detector cell with performance difference. However, there would be some estimation error between a correct projection of the detector cell with performance difference and the estimated projection. Therefore, during the CT image reconstruction, when an image is reconstructed with projections using a filter backprojection method, the estimation error will be back-projected onto the reconstructed image, thereby forming a streak on the reconstructed image, thus affecting the quality of the CT reconstructed image.
Accordingly, it is necessary to provide an improved method for solving at least one of the technical problems as mentioned above.